Long-handled, swingable driving instrument



3,083,969 Patented. Apr. 2, 163

IQQ

3,083,969 LONG-HANDLED, SWHNGABLE DRIVING INSTRUMENT Ciaud H. Bills, In,South Gate, Galif, nssignor to Axalme Golf Company, Sherman Galrs,Caiif., a corporation of California Fiietl Mar. 27, 1961, Ser. No.93,374 Qlaims. (Cl. 273-80) The present invention relates to along-handled, swingable driving instrument in which the handle or shaftis especially designed to control the flexing thereof when theinstrument is swung.

A golf club, for example, is a driving instrument having a long handleor shaft, with a manual gripping means affixed to one end thereof and adriving head aflixed to its other end. As the golf club is swung thehandle or shaft flexes or bends. Although this flexing or bending actioncannot be visually observed it nevertheless has been successfullystudied by means of high speed cameras operating at a rate of severalhundred frames per second. The precise nature of .the flexing or bendingaction that takes place in the handle or shaft not only affects thedriving power which the driving head is capable of imparting to a golfball but may also affect the precision of the direction or aim of thethrust imparted to the golf ball.

According to the present invention a novel shaft construction isprovided which permits individual design for optimum flexing or bendingcharacteristics.

Another feature of the invention is the provision of means for absorbingunwanted shaft vibrations which occur while the golf club or otherinstrument is being swung.

With reference to golf clubs in particular, the types of constructionheretofore known and used have involved a relatively small shaftdiameter at its lower end, where the driving head is attached, and arelatively large diameter at its upper end where the gripping means isattached. There are a number of excellent reasons for this arrangement.The small diameter of the bottom end of the shaft minimizes windresistance, which is considered to be necessary. The larger diameter ofthe upper end the shaft more readily fits the hand of the player.Furthermore, the golf club is in a sense comparable to a whip, and whipsare traditionally of largest diameter at their handle end, hence thegolf club simply would not look right if it had its largest diameter atthe outer end.

So far as known to the applicant there has never been anddissatisfaction with conventional golf club construction, nor has anyneed been recognized for a new type of shaft or handle construction in along-handled, swingable driving instrument. Apparently it has beencommonly believed that conventional golf clubs have been yielding allthe performance that such devices are inherently capable of yielding,and so far as the applicant is advised, he is the first to reach adiiferent conclusion.

One object of the invention, therefore, is to provide means forprecisely con-trolling the flexing or bending action of a swingablehandle or shaft.

Another object of the invention is to provide means for absorbing ordamping upwanted vibrations that occur during the flexing or bending ofa swingable shaft as it is being swung.

A further object of the invention is to provide a golf club capable ofdriving a ball much further than golf clubs heretofore available.

in accordance with the invention a hollow handle or shaft is integrallyformed of metal, preferably a relatively light metal such as aluminum.The wall thickness of the 2 hollow shaft is made uniform throughout thelength of the shaft, except that in a specific portion of the length ofthe shaft the wall thickness is reduced. Flexing or bending of the shaftthen tends to be concentrated in the portion of its length having thereduced wall thickness.

A preferred feature of the invention is to form the reduced wallthickness of the metal in such a way as to avoid any discontinuity. Thatis, both the exterior and interior surfaces of the shaft are smoothlycontinuous surfaces, with the wall thickness changing gradually at bothends of the reduced thickness portion of the shaft.

Another feature of the invention, in its preferred form, is theinclusion in the hollow interior of the metal shaft of a very smallquantity of foamed plastic material. This material breaks the interiorof the shaft into distinct cells or pockets to an extent suificient todisrupt pressure waves that tend to develop in the air cavity within theshaft. Vibrations originating at various points in the shaft structureare therefore dissipated near their point of origin without anopportunity for an oscillatory or recirculating action.

With regard to golf clubs in particular, in accordance with theinvention the old practice of making the shaft smaller at its lower end,to which the driving head is afiixed, is still followed. However, it isrecognized that this type of construction normally tends to producemaximum flexing or bending of the shaft in its smallest diameter portionadjacent its lower end. in accordance with the invention it is alsorecognized that, although the smallest diameter portion needs to be atthe lower end of the shaft, the maximum flexing action needs to beelsewhere. More specifically, the maximum flexing action needs to occursomewhere in the middle portion of the shaft. By utilizing a hollowmetal shaft which tapers in diameter from its upper end to its lowerend, and providing a reduced wall thickness in the middle region of theshaft length, a golf club of superior driving capabilities is achieved.

The objects and advantages of the invention will be more fullyunderstood from the following description in conjunction with theaccompanying drawing, in which:

FIGURE 1 is a side view, partially in cross-section, of a golf club inaccordance with the invention;

FIGURE 2 is a longitudinal cross-sectional view of the golf club shaft;

FIGURE 3 is a longitudinal cross-sectional view of an alternate form ofthe shaft;

FIGURE 4 is a longitudinal cross-sectional view of still another form ofthe shaft in accordance with the in vention.

Referring now to the drawing, the golf club of FIG- URE 1 is seen toinclude an elongated tapered shaft A having a driving head B rigidlyattached to its small or lower end, and a gripping handle C rigidlyattached to its large or upper end. The shaft A is hollow and is filledwith a quantity of foamed plastic material D.

In each of its forms as shown in FIGURES 2-4, inclusive, the shaft A hasan exterior surf-ace 11 whose shape corresponds rather precisely to atruncated cone. The shaft A has a substantially uniform wall thicknessthroughout its length, except for a particular portion of its length inwhich the wall thickness is reduced.

At the lower or small end of the shaft the interior Wall surface 15 isboth concentric to and parallel with the exterior surface 11. During aportion of the shaft length the wall thickness gradually reduces, theinterior Wall surface 16 during this portion of the shaft length beingconcern tric to the exterior surface 11 but not parallel thereto. At thepoint of minimum wall thickness the interior wall surface 17 is bothconcentric to and parallel with the exterior surface 11. During the nextportion of the shaft length the wall thickness increases, the interiorsurface being designed as 18. At 19 the interior surface is againparallel with the exterior surface, and normal wall thickness has beenresumed.

It will be seen that in FIGURE 2 the diminished wall thickness occupiesonly a small portion of the shaft length, immediately above the drivinghead B. In FIGURE 3 the diminished wall thickness also commences abovethe driving head B and extends about twice as for, although by no meansthe entire length of the shaft. In FIGURE 4 the diminished wallthickness extends substantially the entire distance between the innerextremities of the driving head B and gripping handle, C.

The reason for the different lengths of the flex point of the shaft,,asshown in FIGURES 2-4, is to accommodate the needs of different players.Thus the short flex point shown in FIGURE 2 is adapted to a professionalgolfer having a powerful driving stroke, while the long flex pointillustrated in FIGURE 4 is adapted to the average lady golfer.

In the embodiments of the invention as illustrated herein, the shaft Ais integrally formed of aluminum with a basic wall thickness of 0.050inch. Where the wall thickness is reduced its minimum value is 0.030inch. Both the exterior and interior surfaces of the shaft are madesmoothly continuous throughout the shaft length so as to provide agradual wall thickness change at each end of the reduced wall thicknessportion.

In assembling the complete golf club of FIGURE 1 the interior of theshaft is filled with foamed plastic material. A fraction of an ounce ofsolid plastic material is placed inside the hollow shaft, two or threedrops of liquid catalyst are added, and the plastic material then foamsup so as to fi-ll the entire shaft interior. Thereafter the open end ofthe shaft is closed by attaching the gripping handle C. If the plasticfiller were not used the performance of the club would be adverselyaffected by vibrations in the shaft, and on striking the ball therewould be an abnormal hollow sound. However, the plastic fillereliminates the hollow sound; the user may not even know that his clubhas a hollow shaft, and the mechanical vibrations induced by swingingthe shaft are dissipated without adverse effect.

The invention has been described in considerable detain in order tocomply with the patent laws by providing a full public disclosure of atleast one of its forms. However, such detailed descripjtion is notintended in any way to limit the broad features or principles of theinvention, or the scope of patent monopoly to be granted.

I claim:

1. A long-handled-swingable driving instrument comprising an elongatedintegrally formed hollow metal shaft; gripping means affixed to one endof said shaft; and a driving head affixed to the other end of saidshaft; said shaft having a substantially uniform wall thicknessthroughout its length except for a portion of its length in which thewall thickness is reduced, the exterior and interior surfaces of saidshaft being smoothly continuous and providing a gradual wall thicknesschange at each end of said reduced thickness portion; whereby duringswinging of said instrument the maximum flexing of said shaft occurs insaid reduced wall thickness portion there of.

2. A driving instrument as claimed in claim 1 in which the interior ofsaid shaft contains a quantity of foamed plastic material.

3. A golf club shaft comprising an elongated metal tube having arelatively largediameter upper end adapted for attachment ofhand-gripping means thereto and a relatively small-diameter lower endadapted for attachment of a golf club head thereto, said shaft being oftapering diameter throughout its length and having a substantiallyuniform wall thickness at both its ends, a portion of the mid-section ofsaid shaft having a reduced wall thickness whereby the maximum bendingof said shaft occurs in said reduced-wall-thickncss portion thereofrather than in the minimum diameter portion at the lower end of saidshaft, the shaft outer surface corresponding rather precisely to atruncated cone while the shaft inner surface is smoothly curvedthroughout the length of said reduced-wall-thickness portion.

4. An instrument as claimed in claim 1 wherein said metal is aluminum.

5. A golf club shaft as claimed in claim 3 wherein said metal isaluminum.

References Cited in the file of this patent UNITED STATES PATENTS2,085,915 MaCCalhlrn July 6, 1937 FOREIGN PATENTS 465,414- Great BritainMay 5, 1937

1. A LONG-HANDLED-SWINGABLE DRIVING INSTRUMENT COMPRISING AN ELONGATEDINTEGRALLY FORMED HOLLOW METAL SHAFT; GRIPPING MEANS AFFIXED TO ONE ENDOF SAID SHAFT; AND A DRIVING HEAD AFFIXED TO THE OTHER END OF SAIDSHAFT; SAID SHAFT HAVING A SUBSTANTIALLY UNIFORM WALL THICKNESSTHROUGHOUT ITS LENGTH EXCEPT FOR A PORTION OF ITS LENGTH IN WHICH THEWALL THICKNESS IS REDUCED, THE EXTERIOR AND INTERIOR SURFACES OF SAIDSHAFT BEING SMOOTHLY CONTINUOUS AND PROVIDING A GRADUAL WALL THICKNESSCHANGE AT EACH END OF SAID REDUCED THICKNESS PORTION; WHEREBY DURINGSWINGING OF SAID INSTRUMENT THE MAXIMUM FLEXING OF SAID SHAFT OCCURS INSAID REDUCED WALL THICKNESS PORTION THEREOF.